The question of setting definitely at rest the constantly multiplying rumors of wonderful volcanic phenomena around the sources of the Yellowstone, began to be seriously agitated among the people of Montana as early as 1867. An expedition was planned for that year but came to nothing. A like result attended a similar effort the following year. In 1869, the proposition came near materializing, but fell through at the last moment owing to the failure to obtain a military escort. There were three members of this proposed expedition, however, who refused to be frightened off by any dangers which the situation at that time promised. They had already provided themselves with an elaborate equipment, and were determined, with escort or without it, to undertake the trip. The names of these men were David E. Folsom, C. W. Cook, and William Peterson, the last named being a native of Denmark. Armed with "repeating rifles, Colt's six-shooters, and sheath-knives," with a "double-barreled shot gun for small game;" and equipped with a "good field-glass, pocket compass and thermometer," and utensils and provisions "for a six weeks' trip," they set out from Diamond City on the Missouri River, forty miles from Helena, September 6, 1869. The route lay up the Missouri to the Three Forks; thence _via_ Bozeman and Fort Ellis to the Yellowstone River; and thence up the Yellowstone to its junction with the East Fork inside the present limits of the Park. From this point they crossed to the east bank and followed up the river, passing through the many groups of hot springs to be found east of the Grand Cañon. On September 21st, they arrived at the Falls of the Yellowstone, where they remained an entire day. Some distance above the rapids they re-crossed to the west shore and then ascended the river past Sulphur Mountain and Mud Volcano to Yellowstone Lake. They then went to the extreme west shore of the lake and spent some time examining the surpassingly beautiful springs at that point. Thence they crossed the mountains to Shoshone Lake, which they took to be the head of the Madison, and from that point struck out to the north-west over a toilsome country until they reached the Lower Geyser Basin near Nez Percé Creek. Here they saw the Fountain Geyser in action and the many other phenomena in that locality. They ascended the Firehole River to Excelsior Geyser and Prismatic Lake, and then turned down the river on their way home. They were absent on the expedition thirty-six days.